Ever wanted to go back and change one of your Pokémon's nicknames? Well, here's the only place where you can do it. Enter the building close to the south entrance and talk to the Pokémon "name rater" inside. He will only let you change names of Pokémon you captured yourself.

Once a Pokémon is traded, the name sticks -- so be sure to give the Pokémon you're planning to trade with a friend some especially ridiculous names... Oh, and be sure to check out the secrets section to see if there is more to the names.

Don't enter Pokémon Tower just yet. You don't have the necessary tools to engage wild Ghost Pokémon yet, so you can't finish the job. Return here as soon as you've found the Silph Scope -- and start training a Psychic Pokémon to be ready for the enemy. The Silph Scope can be found in Celadon City, which can be reached via Routes 8 and 7.